#include "widget.h"
GLuint VBO, VAO;

Triangle::Triangle()
{
    this->setWindowTitle("Camera");
}

Triangle::~Triangle()
{
    makeCurrent();

    delete ourShader;
    core->glDeleteVertexArrays(1, &VAO);
    core->glDeleteBuffers(1, &VBO);
    delete texture1;
    delete texture2;
}

void Triangle::initializeGL()
{
    //着色器部分
    core = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_3_3_Core>();
    ourShader = new Shader(":/shaders/vertexshadersource.vert", ":/shaders/fragmentshadersource.frag");

    //VAO，VBO数据部分
    float vertices[] =
    {
        -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
            0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
            0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
            0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
            -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
            -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,

            -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
            0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
            0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
            0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
            -0.5f,  0.5f,  0.5f,  0.0f, 1.0f,
            -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,

            -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
            -0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
            -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
            -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
            -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
            -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,

            0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
            0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
            0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
            0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
            0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
            0.5f,  0.5f,  0.5f,  1.0f, 0.0f,

            -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
            0.5f, -0.5f, -0.5f,  1.0f, 1.0f,
            0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
            0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
            -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
            -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,

            -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
            0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
            0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
            0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
            -0.5f,  0.5f,  0.5f,  0.0f, 0.0f,
            -0.5f,  0.5f, -0.5f,  0.0f, 1.0f
        };


    core->glGenVertexArrays(1, &VAO);//两个参数，第一个为需要创建的缓存数量。第二个为用于存储单一ID或多个ID的GLuint变量或数组的地址
    core->glGenBuffers(1, &VBO);

    core->glBindVertexArray(VAO);

    core->glBindBuffer(GL_ARRAY_BUFFER, VBO);
    core->glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    core->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)0);
    core->glEnableVertexAttribArray(0);

    // texture coord attribute
    core->glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)(3 * sizeof(float)));
    core->glEnableVertexAttribArray(1);

    //纹理
    //第一张箱子
    texture1 = new QOpenGLTexture(QImage(":/textures/wall.jpg").mirrored(), QOpenGLTexture::GenerateMipMaps); //直接生成绑定一个2d纹理, 并生成多级纹理MipMaps
    if (!texture1->isCreated())
    {
        qDebug() << "Failed to load texture" << endl;
    }
    texture1->setWrapMode(QOpenGLTexture::DirectionS, QOpenGLTexture::Repeat);// 等于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    texture1->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::Repeat);//    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

    texture1->setMinificationFilter(QOpenGLTexture::Linear);   //等价于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    texture1->setMagnificationFilter(QOpenGLTexture::Linear);  //     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);


    //第二张笑脸
    texture2 = new QOpenGLTexture(QImage(":/textures/awesomeface.png").mirrored(), QOpenGLTexture::GenerateMipMaps); //直接生成绑定一个2d纹理, 并生成多级纹理MipMaps
    if (!texture2->isCreated())
    {
        qDebug() << "Failed to load texture" << endl;
    }
    texture2->setWrapMode(QOpenGLTexture::DirectionS, QOpenGLTexture::Repeat);// 等于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    texture2->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::Repeat);//    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

    texture2->setMinificationFilter(QOpenGLTexture::Linear);   //等价于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    texture2->setMagnificationFilter(QOpenGLTexture::Linear);  //     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    //设置纹理单元编号
    ourShader->use();
    ourShader->setInt("texture1", 0);
    ourShader->setInt("texture2", 1);

    //开启计时器，返回毫秒
    time.start();

    //给着色器变量赋值
    QMatrix4x4 projection;
    // view.translate(QVector3D(0.0f, 0.0f, -3.0f));
    projection.perspective(45.0f, (GLfloat)width() / (GLfloat)height(), 0.1f, 100.0f);

    ourShader->use();
    //ourShader->setMat4("view", view);
    ourShader->setMat4("projection", projection);

    //开启状态
    core->glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    core->glEnable(GL_DEPTH_TEST);
}

void Triangle::resizeGL(int w, int h)
{
    core->glViewport(0, 0, w, h);
}

QVector3D cubePositions[] =         //为了省事，设为全局函数，若嫌封装性不好，改为成员变量指针，在initializeGL()重新赋值就好
{
    QVector3D( 0.0f,  0.0f,  -1.0f), //小小改动一下将z轴的0.0f变为-1.0f
    QVector3D( 2.0f,  5.0f, -15.0f),
    QVector3D(-1.5f, -2.2f, -2.5f),
    QVector3D(-3.8f, -2.0f, -12.3f),
    QVector3D( 2.4f, -0.4f, -3.5f),
    QVector3D(-1.7f,  3.0f, -7.5f),
    QVector3D( 1.3f, -2.0f, -2.5f),
    QVector3D( 1.5f,  2.0f, -2.5f),
    QVector3D( 1.5f,  0.2f, -1.5f),
    QVector3D(-1.3f,  1.0f, -1.5f)
};

void Triangle::paintGL()
{
    core->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    core->glActiveTexture(GL_TEXTURE0);
    texture1->bind();
    core->glActiveTexture(GL_TEXTURE1);
    texture2->bind();

    ourShader->use();

    QMatrix4x4 view;
    GLfloat radius = 15.0f;
    GLfloat camX = sin(((GLfloat)time.elapsed()) / 1000) * radius; //返回的毫秒太大了，除以1000小一些
    GLfloat camZ = cos(((GLfloat)time.elapsed()) / 1000) * radius;
    view.lookAt(QVector3D(camX, 0.0f, camZ), QVector3D(0.0f, 0.0f, 0.0f), QVector3D(0.0f, 1.0f, 0.0f)); // 三个参数：摄像机位置，目标位置，表示世界空间中的上向量
    ourShader->setMat4("view", view);

    for (GLuint i = 0; i != 10; ++i)
    {
        QMatrix4x4 model;
        model.translate(cubePositions[i]);
        model.rotate(20.0f * i, cubePositions[i]);//这里角度改为固定角度


        ourShader->setMat4("model", model);
        core->glBindVertexArray(VAO);
        core->glDrawArrays(GL_TRIANGLES, 0, 36);
    }

    update();
}
